Re: Tri-Q Nose wheel weight


jnmarstall <jnmarstall@...>
 

In my opinion, this is precisely why the reflexor is mandatory for the
Tri-gear. Since we can't directly effect the lifting power of the canard
(after full elevator deflection), the next best thing is to reduce the lift
of the wing which is overpowering the canard during takeoff rotation.
Jerry Marstall
Tri-Q2 210 hrs

----- Original Message -----
From: "Jay Scheevel" <scheevel@...>
To: <Q-LIST@...>
Sent: Tuesday, May 20, 2003 11:03 AM
Subject: Re: [Q-LIST] Re: Tri-Q Nose wheel weight


The real issue is how much weight can elevator lift at full deflection
for various airspeeds. Since the tri-Q needs to rotate in order to take
off, then the elevator has to be capable of lifting the nose wheel at the
desired take-off airspeed.

Although, at a 0-degree pitch angle, and ~150 MPH, the airfoil lift will
match the plane weight the plane will fly, 150 MPH this is not a very
practical take-off speed. Slower than that, the elevator needs to be
able to lift the remaining weight off the nose that is not being carried
by airfoil lift of the flat canard.

The slower the desired take-off speed, the less weight is borne by the
airfoil lift and the more weight must be lifted by elevator deflection.
Since the elevator is a fixed size, and its effectiveness decreases with
decreasing airspeed, the only option you have to lower the take-off speed
is to lighten the nose wheel load by design.

This is the reason why Scott Swing canted the Main gear as far forward as
he did: so the mains would carry ~80% of the load and the nose ~20%. I
suspect that 20% or less of the GW is a good target for the nose. A call
to Scott Swing would also be helpful to your efforts.

You can use the equation that I put in an earlier post (discussing EW CG)
to determine what the appropriate EW main and nose loads should be.

Jay

Original Message <<<<<<<<<<<<<<<<<<
On 5/20/03, 8:14:50 AM, "Ryan" <rryan@...> wrote regarding [Q-LIST]
Re: Tri-Q Nose wheel weight:


Thanks Jay,
This will help me with my Quickie.
The information I am looking for is actual nose & maingear weights
from flying Qs, both EW & loaded Weight.
I would like to see how far from the ideal Canard loading that
takeoff and landing can be performed. This information is to learn
from others how to avoid "Wheelbarrowing the nosewheel" on a new
installation.
Ryan

--- In Q-LIST@..., Jay Scheevel <scheevel@a...> wrote:
The amount of weight on the nose wheel of a loaded airplane can be
computed algebraically as follows:

-- Ma is the Average moment of the gross-weight aircraft
-- GW is the gross weight of the aircraft (this is known: plane,
pilot,
fuel and baggage).
-- CG is the FS of the loaded aircraft. (This is known,at least is
known
to be in the envelope!)
-- MG is the FS of the main gear axles (this is known)
-- NG is the FS of the nose gear axle (this is known)
-- NW is the weight on the Nose gear (this is UNKOWN)
-- MW is the weight on the main gear (this is UNKOWN)

You can construct two equations with two unkowns:

Ma = GW X CG
and
Ma = (NW X NG) + (MW X MG)

We also we know that GW = NW + MW

By substitution and rearrangement of terms these equations can be
reduced
to yield the following ratio:

-- NW/MW = (CG-MG)/(NG-CG)

Notice that the weight terms in the equation disappear in favor of
a
fractional weight ratio. However, depending on how you load the
plane,
your weights will affect the CG value, which will affect this ratio.

For my case with a tri-Q200. The MG=56.5" the NG = 2.0" .
For a typical loading case the CG =46.0"

For this example, the fraction of nose weight to main weight is
0.238 or
19.3% of the total GW load. If we say the GW was 1100 lbs, the
weight on
the nose wheel would be 211.9 pounds (with the other 888.1 on the
mains).

You may have different NG, MG and CG's but the equation will still
work
the same. Just use your measured values for NG, MG and your
anticipated
CG.

As a check of the methodology, one can do the same exercise for the
flying surfaces. Here I replace the terms: NG and MG with the CL of
the
canard (call this CNG) and the CL of the Main Wing (call this MWG).
I
call the canard flying-load (in pounds) CNW and Main wing flying
load in
pounds MWW.

The equation becomes:

-- CNW/MWW = (CG-MWG)/(CNG-CG)

With the Q200 the CNG is approximately 24.0 and the MWG is
approximately
85.0

Plugging these into the equation for a flying CG of 46.0 we get
CNW/MWW =
1.773. Again, using the 1100 lb gross weight, the ratio says that
703.3
lbs is flying on the canard and 396.7 lbs is flying on the main
wing. In
other words, 64% of the total gross weight is being carried by the
canard. These numbers compare favorably with the QAC-advertised
65/35
ratio of load sharing between the canard and mainwing respectively.
So I
think my methodology is sound.

Hope this helps.

Cheers,

Jay


Original Message <<<<<<<<<<<<<<<<<<
On 5/19/03, 7:28:41 PM, "Ryan" <rryan@s...> wrote regarding [Q-
LIST]
Tri-Q Nose wheel weight:


Looks like 25% to 40% is OK for empty weights on the nose of a
Tri-Q.
Does any one have known weights with pilot and full fuel weight?
Ryan

--- In Q-LIST@..., "Ryan" <rryan@s...> wrote:
What percent of the airplane weight should be on the nose
wheel,for
a Tri-Q ?

Ryan


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